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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        //向对象中添加方法 up down;
        let game = {
        }
        //声明一个对象;
        let  methods= {
            up: Symbol(),
            down:Symbol()
        };
        game[methods.up] = function(){
           console.log("schbjsjknjksxskl") 
        }
        game[methods.down]= function(){
            console.log("ijcscs");
        }
        
    </script>
</body>
</html>